My favourite thing was the implication that Anne was regularly writing steamy letters to Gilbert.
I also liked Katherine and particularly

that she does not get her problems solved via marriage

.
The bullying in the first section was pretty tough to read about, as poor Anne has half the town against her and the rest too scared to do anything about it.
I also didn't enjoy the lengthy monologues by people just telling their random family histories etc. Please be a little bit relevant to the plot....

I just want Anne and Gilbert to get married! DX 
That being said, this was a fun book. Most of it was in letters from Anne to Gilbert, so the format change was a little unexpected because there are occassional chapters that are traditional narratives. But while waiting for Gilbert to finish medical school, Anne takes a job as a high school principal, and in traditional Anne fashion finds herself in hijinks not included to a feud with the most prominent family in town before she even arrives and matchmaking, but also charming everyone she meets. 

My rating scale, for reference:

 
I liked Anne as a character in this book. I liked the way she viewed the world, and I liked her optimism, her refusal to give up on even the most prickly of people, and the gift she had for lifting and brightening the lives of those around her.

I liked the setting of this book: Anne’s cozy tower room, the garden gate through which she spoke with little Elizabeth, the graveyard she walked through when she needed to think, the groves of trees, the red ribbon of road with white houses, the blue hill Anne nicknamed the Storm King, the blustery storms…

And I liked Montgomery’s poetic writing style, as always.

But plot wise? It pains me to say that this book was not very interesting. Sure, I enjoyed watching Anne (spoiler)

win over the Pringles (even if it was mostly their fear that she would reveal their “cannibalistic family secret” that won them over vs. her natural charm)

. And I enjoyed reading about her relationships with some of the people in Summerside, particularly Elizabeth, Katherine, the Aunts and Rebecca Dew. But otherwise, it was mostly a lot of talk and gossip of random people, sometimes through the lens of their relatives and distant relatives. Take this sentence from page 276, for example:

“There is an attractive Palmer girl who is reported to be throwing herself at his head, and his sister is said to have said that his mother has said that her son has no need to dangle for years at any girl's apron-string.”

If I don’t know or care about the first person you’re mentioning, I’m for sure not going to care about who they’re related to or how their multiple-removed connections think or feel about a situation. And this is what the bulk of the book seemed to consist of: little stand-alone / incoherent vignettes of Anne interacting with the locals in gossipy ways that I honestly didn’t find very compelling. This makes me feel sad, because this is Anne of Green Gables we're talking about! There’s so much childhood nostalgia wrapped up in the Anne stories for me, but I've found that the further away I've gotten from the original book, the more these books have felt rambly and full of convoluted connections and talk of people who were introduced on one page and then disappeared a few pages later.

And, apart from a few key people (like little Elizabeth), these superficial connections or interactions seemed to happen at the expense of any real connections. When Anne went home for visits to Green Gables, for example, we hardly heard anything about the people she’s loved her whole life. Marilla, Diana Barry, and her adopted younger siblings barely got a mention. Even Gilbert! It was weird because most of the book was written as letters to him (oddly, with any lovey-dovey bits redacted), but we didn’t get anything from his point of view, nor did we get any scenes of Anne and Gilbert together. And then when Anne left Summerside after 3 years of living there, it was only the people she was leaving behind that seemed to feel sad at her departure; Anne herself didn't really seem to care all that much. So the book was chalk-full of superficial connections but lacked the magic and depth of Anne's prior connections and friendships. 

A large part of this book is various characters complaining or being grouchy. It gets a bit tiresome, In my opinion. My favorite parts of this book were the summers back in Avonlea

I picked up Anne of Windy Poplars because I desperately needed a book that was going to be heartwarming and sweet and lift me up because I’ve been feeling so gloomy lately. Anne of Green Gables is one of my favorite books of all time. I was hoping that this, the fourth book in the series, will give me that same warm feeling. It didn’t.

Anne Shirley is growing up. No – she is grown up. While we can expect this to happen to any child, there’s something particularly disappointing to watch Anne grow up because her childlike imagination and innocence is so touching to read about. It was the strangest thing to read Anne of Windy Poplars and watch Anne Shirley take walks with her neighbor Elizabeth, and to have Elizabeth waxing poetical about the world and all the possibilities of tomorrow through Anne’s eyes. The same fancies that would have certainly come from Anne’s mouth just a couple of books ago are now sweet and foreign to her. Childish fancies.

Much of the book is filled with that sort of resignation that the reader must have – Anne is not a child anymore. She is a teacher, she is engaged, and she is responsible for helping so many young couples get married. I do believe there were at least four different weddings that were somehow arranged or contrived with Anne’s assistance in one way or another in this book alone. Not only did Anne feel grown up, other than the older women she was living with, Anne feels like the oldest character in this book. And, oh I don’t know, I guess it made my heart ache a little.

There’s nothing wrong with growing up I suppose. The loss of innocence is always a sad thing, but the loss of fancy and imagination I think it’s just as hard for me to see, and in a character like Anne Shirley where this brought her absolutely off the page and into our hearts, seeing her trodden down by the banalities of life and becoming just another female character in a series of books by an author who likes to write about the young women of Prince Edward Island, she somehow loses her remarkableness. In the same breath, her adulthood reminds us of our own shackles to societal whims.

Anne of Windy Poplars is a perfectly acceptable book in many ways. Montgomery‘s writing is just as flourished and lovely as ever, and we still get snippets of the lives of the people in Anne’s world. There is no moment in this book that will make it stand out in my memory, although Rebecca Do’s character is a delight. This book also contains the “g” word (the one used as a slur against the Romani people), and though it is never used in a negative context, I think it is important to note its presence.

Beyond the disappointment of Anne just becoming another person instead of the remarkable young woman she was in the earlier books, there is the issue of gender to speak about. These books were written in the early 20th century, and gender views were not so broad back then. Anne’s success as a teacher was surely the revelation of a young, independent women to readers of the time. This is the strongest moment of feminism in the book. There are far, far too many passages focusing on external beauty to be quite comfortable, especially the constant reassurances that Anne is beautiful despite her traits. And every single young women in this book, and even some of the older ones, are focused around the idea of their worth being equal to their place in the household and securing a good marriage. I just couldn’t enjoy it. Our world is a different place now, and we treat different genders with much more respect and autonomy than we used to. It is difficult to go back and read works that assume all of the roles we have fought to shed are admirable norms. It’s more tiring than offensive, but the repetition of the theme grated on me.

I don’t think I would recommend Anne of Windy Poplars to any except folks who deeply love the Green Gables series. This book requires some background knowledge on Anne in order for it to be a successful read, but because Anne is displaced from Green Gables for most of the book, I can’t imagine anything happens here that will be missed if the book is skipped all together. It is dull and a bit disappointing, and I know Montgomery can do better. And, selfishly, it left me with more irritation than the feel good feeling I wanted, so I’m a bit prejudiced against it.